Study Suggests Rising Obesity Prevalence May Have Altered Perceptions of Healthy Body Weights

Anouk Garaets, PhD
Credit: University of Luxembourg

New research from the World Health Organization suggests adolescents may be falling out of touch with perceptions of healthy body weight.

An analysis of more than 745,000 adolescents from 41 countries recorded between 2002-2018, results offer insight into the changing perceptions of body weight among adolescents since the turn of the century, with underestimation of weight status increasing and overestimation of weight status decreased over time among both genders during the study period.¹

“During this impressionable age, body weight perception may influence a young person’s lifestyle choices, such as the amount and types of food they eat and their exercise habits,” said lead investigator Anouk Geraets, PhD, of the Department of Social Sciences at the University of Luxembourg.² “So, it’s concerning that we’re seeing a trend where fewer adolescents perceive themselves as being overweight – as this could undermine ongoing efforts to tackle increasing levels of obesity in this age group. Young people who underestimate their weight and therefore do not consider themselves to be overweight may not feel they need to lose excess weight and, as a result, they may make unhealthy lifestyle choices.”

Outside of the COVID-19 pandemic, many in medicine argue obesity has been the most urgent public health crisis for more than decade. According to the US Centers for Disease Control and Prevention, the age-adjusted prevalence of obesity increased from 30.5% to 42.4% between 1999-2000 and 2017-2018, with the prevalence of severe obesity increasing from 4.7% to 9.2% during the same time period.³ With this change in prevalence, which has been seen across the global to varying extents, reports of changes in actual and perceived weight status among adolescents have come forth.¹

Citing a lack of data on time trends as it pertains to body weight perceptions, Geraets and a team of investigators designed the current study as a cross-national analysis of time trends in body weight perception Among children within the Health Behavior in School-Aged Children (HBSC) study. Recording data from 2002-2018, the HBSC study included 5 survey cycles occurring in 2002, 2006, 2010, 2014, and 2018, and offered investigators with data related to a cohort of 746,121 adolescents from 41 countries. This cohort had a mean age of 13.7 (Standard Deviation [SD], 1.6) years and 51.0% were women.¹

In the study, perceived body weight was assessed with the question: Do you think your body is? The responses to this question could include “much too thin”, “a bit too thin”, “about the right size”, “a bit too fat”, and much too fat”. Investigators defined weight status as underweight, normal weight, and overweight/obese. For the purpose of analysis, weight status and perceived weight status were coded numerically.¹

For the purpose of analysis, multilevel logistic models were used to estimate cross-national linear time trends in adolescent body weight perceptions. Investigators noted these models were adjusted for gender, age, and family affluence. Following estimations, investigators assessed whether country-level changesin prevalence of overweight/obesity over time might explain these trends in body weight perception.¹

The overall prevalence of self-reported overweight or obesity in the study population was 14.4%, with rates of 11.5% among women and 17.4% among men. During the entire study period, results suggest 60.9% of participants had correct weight perception, 13.67% underestimated their weight status, and 25.4% overestimated their weight status.¹

Upon analysis, investigators found significant interactions among women based on survey year for correct weight perception (Odds Ratio [OR], 1.011; 95% Confidence Interval [CI], 1.009-1.012; P < .001), underestimation of weight status (OR, 1.005; 95% CI, 1.003-1.008; P < .001), and overestimation of weight status (OR, 0.994; 95% CI, 0.992-0.996; P < .001), which they noted suggests time trends differed by gender. In gender-stratified analyses, males exhibited a decrease in correct weight perception (OR, 0.995; 95% CI, 0.994-0.997; P < .001), while girls reported an increase in correct weight perception (OR, 1.007; 95% CI, 1.006-1.008; P < .001). Investigators also pointed out underestimation of weight status increased over time among both genders, but this time trend was slightly stronger among girls (OR, 1.022; 95% CI, 1.020-1.024; P < .001) compared to boys (OR, 1.015; 95% CI, 1.013-1.016; P < .001).¹

When examining differences between countries, results provided evidence indicating significant unexplained variance across countries. Overall, 15 of 41 countries demonstrated an increase in correct weight perception, 8 showed a decrease in weight perception, and 22 showed an increase in underestimation of weight status.¹

“This study has clinical and public health implications. The increase in correct weight perception and the decrease in overestimation may have a positive effect on unnecessary and unhealthy weight loss behaviors among adolescents, while the increase in underestimation might indicate the need for interventions to strengthen correct weight perception,” Garaets added.²

References:

1. Geraets AF, Cosma A, Fismen A-S, et al. Cross-national time trends in adolescent body weight perception and the explanatory role of overweight/obesity prevalence. Child and Adolescent Obesity. 2023;6(1). doi:10.1080/2574254x.2023.2218148
2. Taylor and Francis Newsroom. Fewer teens now perceive themselves as overweight – international study of more than 745,000 adolescents. EurekAlert! July 3, 2023. Accessed July 6, 2023. https://www.eurekalert.org/news-releases/994002.
3. Products - data briefs - number 360 - February 2020. Centers for Disease Control and Prevention. February 27, 2020. Accessed July 6, 2023. https://www.cdc.gov/nchs/products/databriefs/db360.htm.